JP2002241495A - New 1,3-benzoxazine monomer bearing propargyl ether group and polybenzoxazine obtained by polymerizing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel 1,3-benzoxazine monomer bearing a propargyl ether group and a polybenzoxazine excellent in heat resistance obtained by polymerizing the monomer. SOLUTION: The new 1,3-benzoxazine monomer bearing a propargyl ether group represented by the formula is synthesized, and the monomer is subjected to heat polymerization to give the polybenzoxazine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel 1,3-benzoxazine monomer having a propargyl ether group and a polybenzoxazine obtained by polymerizing the monomer.

[0002]

2. Description of the Related Art A benzoxazine monomer undergoes ring-opening polymerization by heating to produce polybenzoxazine which is a cured product (polymer). This cured product has excellent thermal stability, flame retardancy, dimensional stability, and electrical characteristics, and is a new type of resin that replaces epoxy resins and phenolic resins known as conventional thermosetting resins. It is attracting attention. For example, it is useful as a sealing material for electronic components, a substrate material for circuits, a sliding material used for brakes and the like, and is also suitable as a precursor for making a heat-resistant carbide. .
In addition, polybenzoxazine can be easily molded from a melt of benzoxazine monomer, and can polymerize the benzoxazine monomer without releasing polymerization reaction by-products during the molding. It has advantageous features such as improvement in yield and suppression of foaming during molding.

[0003] Studies on 1,3-benzoxazine monomers have been conducted for a long time.
No. 7,378 discloses a polymerizable product obtained by reacting aniline, phenol and formaldehyde. Attempts have been made to introduce various substituents into the benzene ring of aromatic primary amines represented by aniline, but "Low HY and Ishida H. (1999) Polymer
40, 4365. "discloses a 1,3-benzoxazine monomer having a terminal ethynyl group or a phenylethynyl group.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel 1,3-benzoxazine monomer having a propargyl ether group and a polybenzoxazine having excellent heat resistance obtained by polymerizing the monomer. I do.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by reacting p-aminophenylpropargyl ether with a phenolic compound and formaldehyde, a propargyl ether group was formed. The present inventors have found that a novel 1,3-benzoxazine monomer can be obtained, and that polybenzoxazine having excellent heat resistance can be obtained by polymerizing the monomer, thereby completing the present invention.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION 1,3- represented by Chemical Formula 3 of the present invention
Benzoxazine monomers can be formed from the reaction of p-aminophenylpropargyl ether with a phenolic compound and an aqueous formalin solution in a suitable amount of solvent.

[0007]

Embedded image (Wherein, n is an integer of 1 to 3, R is hydrogen, carbon number 1
Or (I) to (4)
(X) represents a monovalent to trivalent organic group or an inorganic group. )

[0008]

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As an example of the 1,3-benzoxazine monomer of the present invention, in the case of a reaction system of p-aminophenylpropargyl ether, phenol and formaldehyde, a monofunctional benzoxazine monomer represented by Chemical Formula 5 is synthesized. .

[0010]

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Representative phenol compounds used in the present invention include, for example, phenol, cresol, 2-bromo-
4-methylphenol, 2-allylphenol, 1,4
Monofunctional phenols such as aminophenol, phenol naphthalene, biphenol, bisphenol F, 4,
Bifunctional phenols such as 4'-dihydroxybenzophenone, bisphenol A, 1,8-dihydroxyanthraquinone, 1,6-dihydroxynaphthalene, 2,2'-dihydroxyazobenzene, resorcinol, fluorene bisphenol, or 1,3,5-tri Examples include trifunctional phenols such as hydroxybenzene, and polyvinyl phenol.

The organic solvents used in the reaction include dioxane, tetrahydrofuran, dimethylformamide, acetonitrile, dimethylsulfoxide, 1,3-
And dimethylimidazolidinone.

Polybenzoxazine can be obtained by heating and polymerizing (curing) the 1,3-benzoxazine monomer. It is considered. That is, at the same time as the ring-opening polymerization of the benzodioxazine monomer occurs (I → II), the propargyl ether group becomes 2H-chromene by Claisen rearrangement (II → II).
I) It is considered that the polymer is further thermally polymerized to form a network (III → IV).

[0014]

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[0015]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. The 4-aminophenylpropargyl ether used in the present invention was synthesized by the methods shown in Reference Examples 1 and 2.

Reference Example 1 <Synthesis of 4-nitrophenylpropargyl ether> 1
In a L flask, p-nitrophenol (400 mmol, 55.644 g) was dissolved in a sodium hydroxide aqueous solution (400 mmol, 16 g of NaOH dissolved in 500 ml of water). The mixture was heated at 70 ° C until a clear orange solution. To this solution was added 0.04 mole of tetrabutylammonium bromide as a phase transfer catalyst.
Then propargyl bromide (420 mmol, 49.96
A solution of g) in 200 ml of toluene was added dropwise to the above mixture, and the resulting solution was stirred for 24 hours while maintaining the temperature at 60 ° C. The reaction mixture was cooled and the precipitated pale yellow crystals were collected by filtration. Further, the toluene layer was separated and washed with water several times, and the toluene layer was concentrated under reduced pressure to obtain yellow crystals. The obtained crystals were dissolved in dioxane, and this solution was poured into water to remove water-soluble salts. This step was performed several times until colorless crystals were obtained (66 g, 93% yield). The obtained crystals were purified by sublimation under vacuum to obtain colorless crystals having a melting point of 114 to 115 ° C (63 g, 92%).

Reference Example 2 <Synthesis of 4-aminophenylpropargyl ether> The 4-aminophenylpropargyl ether obtained in Reference Example 1 was placed in a 2 L beaker equipped with a stirrer.
Nitrophenylpropargyl ether (180 mmol, 31.89 g) and 700 ml of dioxane were added.
The resulting clear solution was cooled to about 10 ° C. in an ice bath and the cooled tin (II) chloride dihydrate (900 mmol,
203.06 g) in 500 ml of concentrated hydrochloric acid.
The solution was added dropwise while maintaining the temperature. After completion of the dropwise addition, the reaction mixture was heated to room temperature and stirred at room temperature for 2 days. The yellow reaction mixture was neutralized with a cooled 30% aqueous sodium hydroxide solution, extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure to obtain a yellowish brown viscous residue (25 g). The crude product is purified by distillation under reduced pressure to obtain a colorless viscous liquid 2
3 g (86% yield) were obtained. It crystallized in the refrigerator.

Example 1 <Synthesis of Monofunctional Benzoxazine Monomer Having Propargyl Ether Group> A 500% flask was charged with 37% formalin (200 mmol, 16.23 g) and 100 ml of dioxane, cooled in an ice bath and cooled. A solution of p-aminophenylpropargyl ether (100 mmol, 14.71 g) obtained in Reference Example 2 in 100 ml of dioxane was added dropwise while maintaining the temperature at not more than 5 ° C, and the mixture was stirred at 5 ° C or less for 30 minutes. Further phenol (100 mmol, 9.4
A solution of 1 g) in 100 ml of dioxane was added, and the mixture was heated under reflux at 110 ° C. for 5 hours. Next, dioxane was removed under reduced pressure while maintaining the temperature at 50 ° C. The obtained viscous liquid (2
5.5 g) was dissolved in 200 ml of ether, washed with a 3N aqueous solution of sodium hydroxide, and the ether was distilled off under reduced pressure to obtain a yellow viscous liquid (19 g, 67%).

The obtained compound (hereinafter abbreviated as P-appe) was confirmed to have a structure represented by Chemical Formula 7 by ¹ H-NMR and IR spectrum analysis. The NMR spectrum data was as follows. _{^{1 H-NMR (CDCl 3)}} : δ = 7.1~6.8 (m, 8H), 5.28 (s, 2H), 4.61
The (s, 2H), 4.56 (s, 2H) and 2.49 (s, 1H) IR spectrum data were as follows. IR (cm ⁻¹ , the number in parentheses indicates transmittance): ν = 3272 (40),
3045 (55), 2900 (53), 2860 (54), 2225 (76), 1610 (57),
1588 (48), 1513 (33), 1491 (36), 1460 (40), 1373 (51), 1
338 (57), 1310 (51), 1227 (33), 1160 (53), 1116 (60), 1
090 (67), 1031 (37), 973 (50), 944 (39), 847 (44), 762
(40), 678 (58).

[0020]

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Example 2 <Synthesis of Bifunctional Benzoxazine Monomer Having Propargyl Ether Group> 37% formalin (200 mmol, 16.23 g) and 100 ml of dioxane were added to a 500 ml flask, and cooled in an ice bath. A solution of p-aminophenylpropargyl ether (100 mmol, 14.71 g) obtained in Reference Example 2 in 100 ml of dioxane was added dropwise while maintaining the temperature at not more than 5 ° C, and the mixture was stirred at 5 ° C or less for 30 minutes. Further, bisphenol A (50 mmol, 1
A solution of 1.41 g) in 100 ml of dioxane was added and 11
Heating reflux at 0 ° C. was performed for 5 hours. Next, dioxane was removed under reduced pressure while maintaining the temperature at 50 ° C. The obtained viscous liquid (23 g) was dissolved in 200 ml of ether, washed with a 3N aqueous solution of sodium hydroxide, and then ether was distilled off under reduced pressure to obtain yellow crystals (17 g, 64%, melting point: 60-62 ° C.).
I got

The obtained compound (hereinafter abbreviated as B-appe) was confirmed to have the structure represented by Chemical Formula 8 by ¹ H-NMR and IR spectrum analysis. The NMR spectrum data was as follows. _{^{1 H-NMR (CDCl 3)}} : δ = 7.2~6.6, (m, 14H), 5.25 (s, 4H), 4.6
The spectral data of 3 (s, 4H), 4.51 (s, 4H), 2.31 (s, 2H), 2.05 (s, 6H) IR were as follows. IR (cm ⁻¹ , the number in parentheses indicates transmittance): ν = 3385 (44),
3272 (42), 2963 (51), 2864 (65), 2225 (89), 1701 (71),
1610 (57), 1595 (64), 1508 (30), 1443 (61), 1373 (60), 1
225 (37), 1179 (45), 1029 (51), 946 (63), 832 (44).

[0023]

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Example 3 Differential scanning calorimetry (hereinafter abbreviated as DSC) was performed on the P-appe and B-appe obtained in Examples 1 and 2 to determine the starting temperature of heat generation during heating and The maximum exothermic temperature was measured. The test results are as shown in Table 1, and it is considered that heat generation due to ring-opening polymerization of the benzoxazine monomer and heat generation due to Claisen transition and polymerization of propargyl ether occurred.

[0025]

[Table 1]

Example 4 <Polymerization of P-app> P-app obtained in Example 1
e (monomer) was heated at 90 ° C. and poured into a U-shaped glass mold or a solvent-free cast using a glass plate having a thickness of 0.1 to 0.2 mm. The glass surface was previously treated with dichlorodimethylsilane. The mold or cast film is heated under reduced pressure at 120 ° C for 2 hours,
Then at 150 ° C and 180 ° C for 1 hour each for a further 20 hours.
The polymer is heated (polymerized (cured)) by heating in an air oven at 0 ° C. for 2 hours and at 240 ° C. for 1 hour to obtain a corresponding polymer (hereinafter, PP
-Appe).

When the IR spectrum of this polymer was measured, the characteristic absorption band of the benzoxazine ring of the monomer was completely eliminated. A characteristic absorption band of the propargyl group 3272Cm ^-1 and 2225cm ^-1
Was completely disappeared after curing. In contrast, a new peak at 1489 cm ^-1 derived from the tetrasubstituted benzene ring of polybenzoxazine appeared.

Example 5 <Polymerization of B-app> The B-app obtained in Example 2
e (monomer) is polymerized (cured) in the same manner as in Example 4, and the corresponding polymer (hereinafter referred to as BP-app)
e).

When the IR spectrum of the cured product was measured, the peak derived from the monomer disappeared and a new peak derived from the polymer appeared as in the case of Example 4.

The measurement results obtained in Examples 3 to 5 are
And that the 1,3-benzoxazine monomer obtained in Examples 1 and 2 was polymerized (cured) by heating to form a polymer (resin). Can be

[Comparative Examples 1 and 2] As a control of the benzoxazine monomer synthesized in Examples 1 and 2,
According to the method described in JP-A-9-47378, benzoxazine monomers having no propargyl ether group shown in Chemical formulas 9 and 10 were synthesized (hereinafter, abbreviated as Pa and Ba, respectively). Next, these monomers were heated and polymerized in the same manner as in Example 4 to prepare corresponding polymers (hereinafter abbreviated as PP-a and PB-a, respectively).

[0032]

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[0033]

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Example 6 The polymers prepared in Examples 4 and 5 and Comparative Examples 1 and 2 were measured for glass transition temperature, 5% loss on thermal decomposition, and carbonization yield. The test results obtained are as shown in Table 2 and show that the novel polybenzoxazine of the present invention has a higher glass transition temperature than polybenzoxazine having no propargyl ether group, and % Heat decomposition loss point is high, and the carbonization yield is high, it is recognized that it has excellent heat resistance.

[0035]

[Table 2]

[0036]

The 1,3-benzoxazine monomer of the present invention is useful as a raw material for polyoxazine, and a polymer obtained by heating the monomer, that is, polybenzoxazine has excellent heat resistance. Therefore, the utilization effect in the industrial field is great.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C056 AA02 AB01 AC02 AD03 AE02 DA01 DB01 DC04 4J043 PA02 PC065 PC066 PC185 PC186 QA07 RA02 SA35 SA47 SA73 SA81 SB01 UA541 WA07 XA03 XA06 YA13 ZA12 ZB02 ZB50 ZB60

Claims (2)

[Claims] 1. A novel 1,3-benzoxazine monomer having a propargyl ether group represented by the following chemical formula 1. Embedded image (Wherein, n is an integer of 1 to 3, R is hydrogen, carbon number 1
Or (I) to (4)
(X) represents a monovalent to trivalent organic group or an inorganic group. ) 2. A polybenzoxazine obtained by polymerizing the benzoxazine monomer according to claim 1.